;/**
 * Parallax.js
 *
 * @author Matthew Wagerfield - @wagerfield
 * @description Creates a parallax effect between an array of layers,
 *              driving the motion from the gyroscope output of a smartdevice.
 *              If no gyroscope is available, the cursor position is used.
 */(function(window, document, undefined) {

	// Strict Mode
	'use strict';

	// Constants
	var NAME         = 'Parallax';
	var MAGIC_NUMBER = 30;
	var DEFAULTS     = {
		relativeInput: false,
		clipRelativeInput: false,
		calibrationThreshold: 100,
		calibrationDelay: 500,
		supportDelay: 500,
		calibrateX: false,
		calibrateY: true,
		invertX: true,
		invertY: true,
		limitX: false,
		limitY: false,
		scalarX: 10.0,
		scalarY: 10.0,
		frictionX: 0.1,
		frictionY: 0.1,
		originX: 0.5,
		originY: 0.5
	};

	function Parallax(element, options) {

		// DOM Context
		this.element = element;
		this.layers  = element.getElementsByClassName( 'layer' );

		// Data Extraction
		var data = {
			calibrateX: this.data( this.element, 'calibrate-x' ),
			calibrateY: this.data( this.element, 'calibrate-y' ),
			invertX: this.data( this.element, 'invert-x' ),
			invertY: this.data( this.element, 'invert-y' ),
			limitX: this.data( this.element, 'limit-x' ),
			limitY: this.data( this.element, 'limit-y' ),
			scalarX: this.data( this.element, 'scalar-x' ),
			scalarY: this.data( this.element, 'scalar-y' ),
			frictionX: this.data( this.element, 'friction-x' ),
			frictionY: this.data( this.element, 'friction-y' ),
			originX: this.data( this.element, 'origin-x' ),
			originY: this.data( this.element, 'origin-y' )
		};

		// Delete Null Data Values
		for (var key in data) {
			if (data[key] === null) {
				delete data[key];
			}
		}

		// Compose Settings Object
		this.extend( this, DEFAULTS, options, data );

		// States
		this.calibrationTimer = null;
		this.calibrationFlag  = true;
		this.enabled          = false;
		this.depths           = [];
		this.raf              = null;

		// Element Bounds
		this.bounds = null;
		this.ex     = 0;
		this.ey     = 0;
		this.ew     = 0;
		this.eh     = 0;

		// Element Center
		this.ecx = 0;
		this.ecy = 0;

		// Element Range
		this.erx = 0;
		this.ery = 0;

		// Calibration
		this.cx = 0;
		this.cy = 0;

		// Input
		this.ix = 0;
		this.iy = 0;

		// Motion
		this.mx = 0;
		this.my = 0;

		// Velocity
		this.vx = 0;
		this.vy = 0;

		// Callbacks
		this.onMouseMove         = this.onMouseMove.bind( this );
		this.onDeviceOrientation = this.onDeviceOrientation.bind( this );
		this.onOrientationTimer  = this.onOrientationTimer.bind( this );
		this.onCalibrationTimer  = this.onCalibrationTimer.bind( this );
		this.onAnimationFrame    = this.onAnimationFrame.bind( this );
		this.onWindowResize      = this.onWindowResize.bind( this );

		// Initialise
		this.initialise();
	}

	Parallax.prototype.extend = function() {
		if (arguments.length > 1) {
			var master = arguments[0];
			for (var i = 1, l = arguments.length; i < l; i++) {
				var object = arguments[i];
				for (var key in object) {
					master[key] = object[key];
				}
			}
		}
	};

	Parallax.prototype.data = function(element, name) {
		return this.deserialize( element.getAttribute( 'data-' + name ) );
	};

	Parallax.prototype.deserialize = function(value) {
		if (value === "true") {
			return true;
		} else if (value === "false") {
			return false;
		} else if (value === "null") {
			return null;
		} else if ( ! isNaN( parseFloat( value ) ) && isFinite( value )) {
			return parseFloat( value );
		} else {
			return value;
		}
	};

	Parallax.prototype.camelCase = function(value) {
		return value.replace(
			/-+(.)?/g, function(match, character){
				return character ? character.toUpperCase() : '';
			}
		);
	};

	Parallax.prototype.transformSupport = function(value) {
		var element         = document.createElement( 'div' );
		var propertySupport = false;
		var propertyValue   = null;
		var featureSupport  = false;
		var cssProperty     = null;
		var jsProperty      = null;
		for (var i = 0, l = this.vendors.length; i < l; i++) {
			if (this.vendors[i] !== null) {
				cssProperty = this.vendors[i][0] + 'transform';
				jsProperty  = this.vendors[i][1] + 'Transform';
			} else {
				cssProperty = 'transform';
				jsProperty  = 'transform';
			}
			if (element.style[jsProperty] !== undefined) {
				propertySupport = true;
				break;
			}
		}
		switch (value) {
			case '2D':
				featureSupport = propertySupport;
			break;
			case '3D':
				if (propertySupport) {
					var body             = document.body || document.createElement( 'body' );
					var documentElement  = document.documentElement;
					var documentOverflow = documentElement.style.overflow;
					if ( ! document.body) {
						documentElement.style.overflow = 'hidden';
						documentElement.appendChild( body );
						body.style.overflow   = 'hidden';
						body.style.background = '';
					}
					body.appendChild( element );
					element.style[jsProperty]      = 'translate3d(1px,1px,1px)';
					propertyValue                  = window.getComputedStyle( element ).getPropertyValue( cssProperty );
					featureSupport                 = propertyValue !== undefined && propertyValue.length > 0 && propertyValue !== "none";
					documentElement.style.overflow = documentOverflow;
					body.removeChild( element );
				}
			break;
		}
		return featureSupport;
	};

	Parallax.prototype.ww                 = null;
	Parallax.prototype.wh                 = null;
	Parallax.prototype.wcx                = null;
	Parallax.prototype.wcy                = null;
	Parallax.prototype.wrx                = null;
	Parallax.prototype.wry                = null;
	Parallax.prototype.portrait           = null;
	Parallax.prototype.desktop            = ! navigator.userAgent.match( /(iPhone|iPod|iPad|Android|BlackBerry|BB10|mobi|tablet|opera mini|nexus 7)/i );
	Parallax.prototype.vendors            = [null,['-webkit-','webkit'],['-moz-','Moz'],['-o-','O'],['-ms-','ms']];
	Parallax.prototype.motionSupport      = ! ! window.DeviceMotionEvent;
	Parallax.prototype.orientationSupport = ! ! window.DeviceOrientationEvent;
	Parallax.prototype.orientationStatus  = 0;
	Parallax.prototype.transform2DSupport = Parallax.prototype.transformSupport( '2D' );
	Parallax.prototype.transform3DSupport = Parallax.prototype.transformSupport( '3D' );
	Parallax.prototype.propertyCache      = {};

	Parallax.prototype.initialise = function() {

		// Configure Context Styles
		if (this.transform3DSupport) {
			this.accelerate( this.element );
		}
		var style = window.getComputedStyle( this.element );
		if (style.getPropertyValue( 'position' ) === 'static') {
			this.element.style.position = 'relative';
		}

		// Setup
		this.updateLayers();
		this.updateDimensions();
		this.enable();
		this.queueCalibration( this.calibrationDelay );
	};

	Parallax.prototype.updateLayers = function() {

		// Cache Layer Elements
		this.layers = this.element.getElementsByClassName( 'layer' );
		this.depths = [];

		// Configure Layer Styles
		for (var i = 0, l = this.layers.length; i < l; i++) {
			var layer = this.layers[i];
			if (this.transform3DSupport) {
				this.accelerate( layer );
			}
			layer.style.position = i ? 'absolute' : 'relative';
			layer.style.display  = 'block';
			layer.style.left     = 0;
			layer.style.top      = 0;

			// Cache Layer Depth
			this.depths.push( this.data( layer, 'depth' ) || 0 );
		}
	};

	Parallax.prototype.updateDimensions = function() {
		this.ww  = window.innerWidth;
		this.wh  = window.innerHeight;
		this.wcx = this.ww * this.originX;
		this.wcy = this.wh * this.originY;
		this.wrx = Math.max( this.wcx, this.ww - this.wcx );
		this.wry = Math.max( this.wcy, this.wh - this.wcy );
	};

	Parallax.prototype.updateBounds = function() {
		this.bounds = this.element.getBoundingClientRect();
		this.ex     = this.bounds.left;
		this.ey     = this.bounds.top;
		this.ew     = this.bounds.width;
		this.eh     = this.bounds.height;
		this.ecx    = this.ew * this.originX;
		this.ecy    = this.eh * this.originY;
		this.erx    = Math.max( this.ecx, this.ew - this.ecx );
		this.ery    = Math.max( this.ecy, this.eh - this.ecy );
	};

	Parallax.prototype.queueCalibration = function(delay) {
		clearTimeout( this.calibrationTimer );
		this.calibrationTimer = setTimeout( this.onCalibrationTimer, delay );
	};

	Parallax.prototype.enable = function() {
		if ( ! this.enabled) {
			this.enabled = true;
			if (this.orientationSupport) {
				this.portrait = null;
				window.addEventListener( 'deviceorientation', this.onDeviceOrientation );
				setTimeout( this.onOrientationTimer, this.supportDelay );
			} else {
				this.cx       = 0;
				this.cy       = 0;
				this.portrait = false;
				window.addEventListener( 'mousemove', this.onMouseMove );
			}
			window.addEventListener( 'resize', this.onWindowResize );
			this.raf = requestAnimationFrame( this.onAnimationFrame );
		}
	};

	Parallax.prototype.disable = function() {
		if (this.enabled) {
			this.enabled = false;
			if (this.orientationSupport) {
				window.removeEventListener( 'deviceorientation', this.onDeviceOrientation );
			} else {
				window.removeEventListener( 'mousemove', this.onMouseMove );
			}
			window.removeEventListener( 'resize', this.onWindowResize );
			cancelAnimationFrame( this.raf );
		}
	};

	Parallax.prototype.calibrate = function(x, y) {
		this.calibrateX = x === undefined ? this.calibrateX : x;
		this.calibrateY = y === undefined ? this.calibrateY : y;
	};

	Parallax.prototype.invert = function(x, y) {
		this.invertX = x === undefined ? this.invertX : x;
		this.invertY = y === undefined ? this.invertY : y;
	};

	Parallax.prototype.friction = function(x, y) {
		this.frictionX = x === undefined ? this.frictionX : x;
		this.frictionY = y === undefined ? this.frictionY : y;
	};

	Parallax.prototype.scalar = function(x, y) {
		this.scalarX = x === undefined ? this.scalarX : x;
		this.scalarY = y === undefined ? this.scalarY : y;
	};

	Parallax.prototype.limit = function(x, y) {
		this.limitX = x === undefined ? this.limitX : x;
		this.limitY = y === undefined ? this.limitY : y;
	};

	Parallax.prototype.origin = function(x, y) {
		this.originX = x === undefined ? this.originX : x;
		this.originY = y === undefined ? this.originY : y;
	};

	Parallax.prototype.clamp = function(value, min, max) {
		value = Math.max( value, min );
		value = Math.min( value, max );
		return value;
	};

	Parallax.prototype.css = function(element, property, value) {
		var jsProperty = this.propertyCache[property];
		if ( ! jsProperty) {
			for (var i = 0, l = this.vendors.length; i < l; i++) {
				if (this.vendors[i] !== null) {
					jsProperty = this.camelCase( this.vendors[i][1] + '-' + property );
				} else {
					jsProperty = property;
				}
				if (element.style[jsProperty] !== undefined) {
					this.propertyCache[property] = jsProperty;
					break;
				}
			}
		}
		element.style[jsProperty] = value;
	};

	Parallax.prototype.accelerate = function(element) {
		this.css( element, 'transform', 'translate3d(0,0,0)' );
		this.css( element, 'transform-style', 'preserve-3d' );
		this.css( element, 'backface-visibility', 'hidden' );
	};

	Parallax.prototype.setPosition = function(element, x, y) {
		x += 'px';
		y += 'px';
		if (this.transform3DSupport) {
			this.css( element, 'transform', 'translate3d(' + x + ',' + y + ',0)' );
		} else if (this.transform2DSupport) {
			this.css( element, 'transform', 'translate(' + x + ',' + y + ')' );
		} else {
			element.style.left = x;
			element.style.top  = y;
		}
	};

	Parallax.prototype.onOrientationTimer = function(event) {
		if (this.orientationSupport && this.orientationStatus === 0) {
			this.disable();
			this.orientationSupport = false;
			this.enable();
		}
	};

	Parallax.prototype.onCalibrationTimer = function(event) {
		this.calibrationFlag = true;
	};

	Parallax.prototype.onWindowResize = function(event) {
		this.updateDimensions();
	};

	Parallax.prototype.onAnimationFrame = function() {
		this.updateBounds();
		var dx = this.ix - this.cx;
		var dy = this.iy - this.cy;
		if ((Math.abs( dx ) > this.calibrationThreshold) || (Math.abs( dy ) > this.calibrationThreshold)) {
			this.queueCalibration( 0 );
		}
		if (this.portrait) {
			this.mx = this.calibrateX ? dy : this.iy;
			this.my = this.calibrateY ? dx : this.ix;
		} else {
			this.mx = this.calibrateX ? dx : this.ix;
			this.my = this.calibrateY ? dy : this.iy;
		}
		this.mx *= this.ew * (this.scalarX / 100);
		this.my *= this.eh * (this.scalarY / 100);
		if ( ! isNaN( parseFloat( this.limitX ) )) {
			this.mx = this.clamp( this.mx, -this.limitX, this.limitX );
		}
		if ( ! isNaN( parseFloat( this.limitY ) )) {
			this.my = this.clamp( this.my, -this.limitY, this.limitY );
		}
		this.vx += (this.mx - this.vx) * this.frictionX;
		this.vy += (this.my - this.vy) * this.frictionY;
		for (var i = 0, l = this.layers.length; i < l; i++) {
			var layer   = this.layers[i];
			var depth   = this.depths[i];
			var xOffset = this.vx * depth * (this.invertX ? -1 : 1);
			var yOffset = this.vy * depth * (this.invertY ? -1 : 1);
			this.setPosition( layer, xOffset, yOffset );
		}
		this.raf = requestAnimationFrame( this.onAnimationFrame );
	};

	Parallax.prototype.onDeviceOrientation = function(event) {

		// Validate environment and event properties.
		if ( ! this.desktop && event.beta !== null && event.gamma !== null) {

			// Set orientation status.
			this.orientationStatus = 1;

			// Extract Rotation
			var x = (event.beta || 0) / MAGIC_NUMBER; // -90 :: 90
			var y = (event.gamma || 0) / MAGIC_NUMBER; // -180 :: 180

			// Detect Orientation Change
			var portrait = this.wh > this.ww;
			if (this.portrait !== portrait) {
				this.portrait        = portrait;
				this.calibrationFlag = true;
			}

			// Set Calibration
			if (this.calibrationFlag) {
				this.calibrationFlag = false;
				this.cx              = x;
				this.cy              = y;
			}

			// Set Input
			this.ix = x;
			this.iy = y;
		}
	};

	Parallax.prototype.onMouseMove = function(event) {

		// Cache mouse coordinates.
		var clientX = event.clientX;
		var clientY = event.clientY;

		// Calculate Mouse Input
		if ( ! this.orientationSupport && this.relativeInput) {

			// Clip mouse coordinates inside element bounds.
			if (this.clipRelativeInput) {
				clientX = Math.max( clientX, this.ex );
				clientX = Math.min( clientX, this.ex + this.ew );
				clientY = Math.max( clientY, this.ey );
				clientY = Math.min( clientY, this.ey + this.eh );
			}

			// Calculate input relative to the element.
			this.ix = (clientX - this.ex - this.ecx) / this.erx;
			this.iy = (clientY - this.ey - this.ecy) / this.ery;

		} else {

			// Calculate input relative to the window.
			this.ix = (clientX - this.wcx) / this.wrx;
			this.iy = (clientY - this.wcy) / this.wry;
		}
	};

	// Expose Parallax
	window[NAME] = Parallax;

})( window, document );
